The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Vehicles include an internal combustion engine that generates drive torque. More specifically, the engine draws in air and mixes the air with fuel to form a combustion mixture. The combustion mixture is compressed within cylinders and is combusted to drive pistons. The pistons rotatably drive a crankshaft that transfers drive torque to a transmission and wheels. When the engine misfires, the combustion mixture of a cylinder may not combust at all or may combust only partially, and may cause engine vibration and driveline oscillation. A random misfire typically occurs on different cylinders regardless of whether or not they come from consecutive engine cycles.
When a misfire occurs, the speed of the piston can be affected, which in turn can affect the engine speed. Rough roads can also cause changes in engine speed that are similar in magnitude to those generated by engine misfire events. Therefore, rough roads may cause engine misfire detection systems to incorrectly detect engine misfire events.